Kory Hill / Mbed 2 deprecated BMP085_lib

demo program of BMP085 pressure sensor

Dependencies:   mbed

main.cpp@2:8c00953d4755, 2012-11-06 (annotated)

Committer:
tylerjw
Date:
Tue Nov 06 02:39:40 2012 +0000
Revision:
2:8c00953d4755
Parent:
1:2935199329b2
Child:
3:ae2b8103e52b
library initial commit;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
tylerjw 2:8c00953d4755 1 /*
tylerjw 2:8c00953d4755 2 *
tylerjw 2:8c00953d4755 3 * 1.8 - 3.6V (Vdd)
tylerjw 2:8c00953d4755 4 * 1.62 - 3.6 (Vddio)
tylerjw 2:8c00953d4755 5 *
tylerjw 2:8c00953d4755 6 *
tylerjw 2:8c00953d4755 7 *Altitude = 44330*(1-(p/p0)^(1/5.255))
tylerjw 2:8c00953d4755 8 * set p0 to sealevel pressure
tylerjw 2:8c00953d4755 9 * delta p = 1hPa = 8.43m at sea level
tylerjw 2:8c00953d4755 10 *
tylerjw 2:8c00953d4755 11 */
tylerjw 2:8c00953d4755 12
tylerjw 2:8c00953d4755 13 /*
tylerjw 2:8c00953d4755 14 *Pinout:
tylerjw 2:8c00953d4755 15 *pin9 = SDA
tylerjw 2:8c00953d4755 16 *pin10 = SCL
tylerjw 2:8c00953d4755 17 *pin11 = XCLR (digital out; active low; Resets sensor)
tylerjw 2:8c00953d4755 18 *pin12 = EOC ("end of conversation"; signal when conversion finished)
tylerjw 2:8c00953d4755 19 *
tylerjw 2:8c00953d4755 20 */
tylerjw 2:8c00953d4755 21
tylerjw 2:8c00953d4755 22 #include "mbed.h"
tylerjw 2:8c00953d4755 23 #include "BMP085.h"
tylerjw 2:8c00953d4755 24
tylerjw 2:8c00953d4755 25 I2C i2c(p9, p10); // sda, scl
tylerjw 2:8c00953d4755 26 BMP085 alt_sensor(i2c);
tylerjw 2:8c00953d4755 27 Serial pc(USBTX, USBRX); // tx, rx
tylerjw 2:8c00953d4755 28
tylerjw 2:8c00953d4755 29 /*
tylerjw 2:8c00953d4755 30 const int bmp085_address = 0xEE; //address of bmp085
tylerjw 2:8c00953d4755 31 const int P0 = 101325; //pressure at sea level
tylerjw 2:8c00953d4755 32
tylerjw 2:8c00953d4755 33 void bmp085_calibration(void);
tylerjw 2:8c00953d4755 34 void display_calibration(void);
tylerjw 2:8c00953d4755 35 unsigned short read_short(int,int);
tylerjw 2:8c00953d4755 36
tylerjw 2:8c00953d4755 37 void write_char(int,int,int);
tylerjw 2:8c00953d4755 38
tylerjw 2:8c00953d4755 39 long get_raw_temp(void);
tylerjw 2:8c00953d4755 40 void calculations(long);
tylerjw 2:8c00953d4755 41
tylerjw 2:8c00953d4755 42 float get_temperature(void);
tylerjw 2:8c00953d4755 43 long get_pressure(void);
tylerjw 2:8c00953d4755 44 float get_altitude(long);
tylerjw 2:8c00953d4755 45 */
tylerjw 2:8c00953d4755 46
tylerjw 2:8c00953d4755 47 //short AC1, AC2, AC3, B1, B2, MB, MC, MD, OSS;
tylerjw 2:8c00953d4755 48 //unsigned short AC4, AC5, AC6;
tylerjw 2:8c00953d4755 49
tylerjw 2:8c00953d4755 50 int main()
tylerjw 2:8c00953d4755 51 {
tylerjw 2:8c00953d4755 52 pc.baud(9600);
tylerjw 2:8c00953d4755 53 //alt_sensor.display_cal_param(&pc);
tylerjw 2:8c00953d4755 54 while(1)
tylerjw 2:8c00953d4755 55 {
tylerjw 2:8c00953d4755 56 pc.printf("Temperature: %d\r\n", alt_sensor.get_temperature());
tylerjw 2:8c00953d4755 57 pc.printf("Pressure: %d\r\n", alt_sensor.get_pressure());
tylerjw 2:8c00953d4755 58 pc.printf("Altitude: %f\r\n", alt_sensor.get_altitude_ft());
tylerjw 2:8c00953d4755 59
tylerjw 2:8c00953d4755 60 wait(0.5);
tylerjw 2:8c00953d4755 61 }
tylerjw 2:8c00953d4755 62 //Initialize
tylerjw 2:8c00953d4755 63 //OSS = STANDARD; //change between enums under bmp085_oss for desired Sampling resolution
tylerjw 2:8c00953d4755 64
tylerjw 2:8c00953d4755 65 //calibrate
tylerjw 2:8c00953d4755 66 //bmp085_calibration();
tylerjw 2:8c00953d4755 67 //display_calibration();
tylerjw 2:8c00953d4755 68
tylerjw 2:8c00953d4755 69 //long raw_temp = get_raw_temp();
tylerjw 2:8c00953d4755 70
tylerjw 2:8c00953d4755 71 //calculations(raw_temp);
tylerjw 2:8c00953d4755 72
tylerjw 2:8c00953d4755 73 //float altitude = get_altitude(pressure);
tylerjw 2:8c00953d4755 74
tylerjw 2:8c00953d4755 75 //pc.printf("Temperature: %f\n",temperature);
tylerjw 2:8c00953d4755 76 //pc.printf("Pressure: %l\n", pressure);
tylerjw 2:8c00953d4755 77 //pc.printf("Altitude: %f\n", altitude);
tylerjw 2:8c00953d4755 78 }
tylerjw 2:8c00953d4755 79 /*
tylerjw 2:8c00953d4755 80 long get_raw_temp(void)
tylerjw 2:8c00953d4755 81 {
tylerjw 2:8c00953d4755 82 long raw_temp;
tylerjw 2:8c00953d4755 83
tylerjw 2:8c00953d4755 84 //Read raw temperature value
tylerjw 2:8c00953d4755 85 write_char(bmp085_address, 0xF4, 0x2E);
tylerjw 2:8c00953d4755 86 wait_ms(4.5);
tylerjw 2:8c00953d4755 87 raw_temp = read_short(bmp085_address, 0xF6);
tylerjw 2:8c00953d4755 88
tylerjw 2:8c00953d4755 89 return raw_temp;
tylerjw 2:8c00953d4755 90 }
tylerjw 2:8c00953d4755 91
tylerjw 2:8c00953d4755 92 void calculations(long raw_temp)
tylerjw 2:8c00953d4755 93 {
tylerjw 2:8c00953d4755 94 long X1, X2, B5; //temperature;
tylerjw 2:8c00953d4755 95
tylerjw 2:8c00953d4755 96 //Start temperature calculation
tylerjw 2:8c00953d4755 97 X1 = (((long)raw_temp - (long)AC6) * (long)AC5) >> 15;
tylerjw 2:8c00953d4755 98 X2 = ((long)MC << 11) / (X1 + MD);
tylerjw 2:8c00953d4755 99 B5 = X1 + X2;
tylerjw 2:8c00953d4755 100 temperature = ((B5 + 8) >> 4);
tylerjw 2:8c00953d4755 101
tylerjw 2:8c00953d4755 102 temperature = ((float)temperature / 10.0);
tylerjw 2:8c00953d4755 103
tylerjw 2:8c00953d4755 104 pc.printf("Temperature: %f\n",temperature);
tylerjw 2:8c00953d4755 105
tylerjw 2:8c00953d4755 106
tylerjw 2:8c00953d4755 107 long raw_pressure, B6, B3, X3;
tylerjw 2:8c00953d4755 108 unsigned long B4, B7;
tylerjw 2:8c00953d4755 109
tylerjw 2:8c00953d4755 110 //Read raw pressure value
tylerjw 2:8c00953d4755 111 write_char(bmp085_address, 0xf4, 0x34 | (OSS << 6));
tylerjw 2:8c00953d4755 112 wait_ms(5);
tylerjw 2:8c00953d4755 113 raw_pressure = read_short(bmp085_address, 0xF6) >> (8 - OSS);
tylerjw 2:8c00953d4755 114
tylerjw 2:8c00953d4755 115 //Start Pressure calculation
tylerjw 2:8c00953d4755 116 B6 = B5 - 4000;
tylerjw 2:8c00953d4755 117 X1 = (B2 * (B6 * B6) >> 12) >> 11;
tylerjw 2:8c00953d4755 118 X2 = (AC2 * B6) >> 11;
tylerjw 2:8c00953d4755 119 X3 = X1 + X2;
tylerjw 2:8c00953d4755 120 B3 = (((AC1 * 4 + X3) << OSS + 2) / 4);
tylerjw 2:8c00953d4755 121 X1 = (AC3 * B6) >> 13;
tylerjw 2:8c00953d4755 122 X2 = (B1 * ((B6 * B6) >> 12)) >> 16;
tylerjw 2:8c00953d4755 123 X3 = ((X1 + X2) + 2) >> 2;
tylerjw 2:8c00953d4755 124 B4 = (AC4 * (unsigned long)(X3 + 32768)) >> 15;
tylerjw 2:8c00953d4755 125 B7 = ((unsigned long)(raw_pressure - B3) * (50000 >> OSS));
tylerjw 2:8c00953d4755 126 if (B7 < 0x80000000)
tylerjw 2:8c00953d4755 127 pressure = (B7 *2) / B4;
tylerjw 2:8c00953d4755 128 else
tylerjw 2:8c00953d4755 129 pressure = (B7 / B4) * 2;
tylerjw 2:8c00953d4755 130
tylerjw 2:8c00953d4755 131 X1 = (pressure >> 8) * (pressure >>8);
tylerjw 2:8c00953d4755 132 X1 = (X1 * 3038) >>16;
tylerjw 2:8c00953d4755 133 X2 = (-7357 * pressure) >>16;
tylerjw 2:8c00953d4755 134 pressure += (X1 + X2 + 3791)>>4;
tylerjw 2:8c00953d4755 135
tylerjw 2:8c00953d4755 136 pc.printf("Pressure: %f\n", pressure);
tylerjw 2:8c00953d4755 137
tylerjw 2:8c00953d4755 138 }
tylerjw 2:8c00953d4755 139
tylerjw 2:8c00953d4755 140 float get_temperature(void)
tylerjw 2:8c00953d4755 141 {
tylerjw 2:8c00953d4755 142 return temperature;
tylerjw 2:8c00953d4755 143 }
tylerjw 2:8c00953d4755 144
tylerjw 2:8c00953d4755 145 long get_pressure(void)
tylerjw 2:8c00953d4755 146 {
tylerjw 2:8c00953d4755 147 return pressure;
tylerjw 2:8c00953d4755 148 }
tylerjw 2:8c00953d4755 149
tylerjw 2:8c00953d4755 150 float get_altitude(long pressure)
tylerjw 2:8c00953d4755 151 {
tylerjw 2:8c00953d4755 152 float altitude;
tylerjw 2:8c00953d4755 153
tylerjw 2:8c00953d4755 154 altitude = (float)44330 * (1 - pow(( pressure/P0), 0.190295));
tylerjw 2:8c00953d4755 155
tylerjw 2:8c00953d4755 156 pc.printf("Altitude: %f\n", altitude);
tylerjw 2:8c00953d4755 157 return altitude;
tylerjw 2:8c00953d4755 158
tylerjw 2:8c00953d4755 159 }
tylerjw 2:8c00953d4755 160
tylerjw 2:8c00953d4755 161 void bmp085_calibration(void)
tylerjw 2:8c00953d4755 162 {
tylerjw 2:8c00953d4755 163 AC1 = read_short(bmp085_address, 0xAA);
tylerjw 2:8c00953d4755 164 AC2 = read_short(bmp085_address, 0xAC);
tylerjw 2:8c00953d4755 165 AC3 = read_short(bmp085_address, 0xAE);
tylerjw 2:8c00953d4755 166 AC4 = read_short(bmp085_address, 0xB0);
tylerjw 2:8c00953d4755 167 AC5 = read_short(bmp085_address, 0xB2);
tylerjw 2:8c00953d4755 168 AC6 = read_short(bmp085_address, 0xB4);
tylerjw 2:8c00953d4755 169 B1 = read_short(bmp085_address, 0xB6);
tylerjw 2:8c00953d4755 170 B2 = read_short(bmp085_address, 0xB8);
tylerjw 2:8c00953d4755 171 MB = read_short(bmp085_address, 0xBA);
tylerjw 2:8c00953d4755 172 MC = read_short(bmp085_address, 0xBC);
tylerjw 2:8c00953d4755 173 MD = read_short(bmp085_address, 0xBE);
tylerjw 2:8c00953d4755 174
tylerjw 2:8c00953d4755 175 }
tylerjw 2:8c00953d4755 176
tylerjw 2:8c00953d4755 177 void display_calibration(void)
tylerjw 2:8c00953d4755 178 {
tylerjw 2:8c00953d4755 179 pc.printf("Calibration Values:\n");
tylerjw 2:8c00953d4755 180 pc.printf("AC1 = %d\n",AC1);
tylerjw 2:8c00953d4755 181 pc.printf("AC2 = %d\n",AC2);
tylerjw 2:8c00953d4755 182 pc.printf("AC3 = %d\n",AC3);
tylerjw 2:8c00953d4755 183 pc.printf("AC4 = %d\n",AC4);
tylerjw 2:8c00953d4755 184 pc.printf("AC5 = %d\n",AC5);
tylerjw 2:8c00953d4755 185 pc.printf("AC6 = %d\n",AC6);
tylerjw 2:8c00953d4755 186 pc.printf("B1 = %d\n",B1);
tylerjw 2:8c00953d4755 187 pc.printf("B2 = %d\n",B2);
tylerjw 2:8c00953d4755 188 pc.printf("MB = %d\n",MB);
tylerjw 2:8c00953d4755 189 pc.printf("MC = %d\n",MC);
tylerjw 2:8c00953d4755 190 pc.printf("MD = %d\n",MD);
tylerjw 2:8c00953d4755 191 }*/
tylerjw 2:8c00953d4755 192